1. Field of the Invention
The present invention relates generally to a device that can be used for measuring the leg length of individuals that may have an anatomical leg length imbalance due to fracture, congential anomaly, or pelvic distortion (musle imbalance), and particularly to such a device which is capable of making desired leg measurements on persons in a supine position by closely approximating the conditions of a person standing upright.
2. Description of the Prior Art
Many medical practitioners have made it a practice to take pelvis-lumbar X-ray films of patients disposed in the upright or "posture" position, only to be disappointed in the quality of film obtained due to the gravitational pull on the abdominal viscera of the patient, giving an off-center picture if an anatomical imbalance is present. Further, the quality of the pictures obtained can be poor due to body movement of the patient. The measures usually taken to minimize the above problems only distort the ossious anatomy further, making the "posture" X-ray of questionable value. Therefore, many practitioners have abandoned the traditional posture film for the conventional supine position that will give better detail in the resulting pictures, but lacks the weight bearing effect, or spine-limb compression, obtained in a standing subject.
U.S. Pat. No. 2,712,696, issued July 12, 1955, to H. L. Johnson, discloses an example of a known pelvic leveling and leg measuring machine, while U.S. Pat. No. 3,520,293, issued July 14, 1970, to C. H. Atherholt, discloses an anthropometric apparatus particularly for actually measuring the length of legs, or for detecting legs of unequal length, of a subject in a supine position under conditions closely approximating those existing while a person is standing. The latter mentioned prior patent, U.S. Pat. No. 3,520,293, employs independently movable foot engaging members from applying force approximately one-half the weight of the person to each foot so as to duplicate the standing conditions. Further, U.S. Pat. No. 3,629,581, issued Dec. 21, 1971, to J. P. Smith, discloses a device for positioning a patient's shoulders during X-ray examination, wherein the patient pulls against the feet of the patient with both hands by means of a vertically disposed foot rest having attached thereto a pair of flexible elongated members engageable by the hands and wrist of the patient.
U.S. Pat. No. 2,349,664, May 23, 1944, to F. G. Leighty, discloses a frame for measuring body posture with the subject in a standing position, while U.S. Pat. Nos. 1,370,640, issued March 8, 1921, to A. Granger; 1,902,558, issued Mar. 21, 1933, to C. R. Johnson; 2,194,990, issued Mar. 26, 1940, to R. Torpin; 2,709,084, issued Apr. 23, 1957, to H. W. O'Dell et al; 3,723,743, issued Mar. 27, 1973, to D. D. Brackenbrough et al; and 3,974,388, issued Aug. 10, 1976, to W. Distler et al, disclose various examples of devices used for positioning a human torso, and/or protecting specific parts of the torso, during X-ray examination of the subject.